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MXS-852: Use stored query type for COM_STMT_EXECUTE

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When a COM_STMT_EXECUTE or a COM_STMT_SEND_LONG_DATA command is executed,
the query type of the prepared statement is used. This allows read-only
prepared statements to be load balanced across slaves.
This commit is contained in:
Markus Mäkelä
2017-06-21 16:27:31 +03:00
parent 77f78c4b20
commit 3c4e1e3b4b
6 changed files with 61 additions and 31 deletions
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2
include/maxscale/backend.hh
View File

@ -159,7 +159,7 @@ public:
*
* @return True if data was written successfully
*/
bool write(GWBUF* buffer, response_type type = EXPECT_RESPONSE);
virtual bool write(GWBUF* buffer, response_type type = EXPECT_RESPONSE);
/**
* @brief Write an authentication switch request to the backend server

10
include/maxscale/protocol/mysql.h
View File

@ -537,12 +537,14 @@ uint8_t mxs_mysql_get_command(GWBUF* buffer);
bool mxs_mysql_extract_ps_response(GWBUF* buffer, MXS_PS_RESPONSE* out);
/**
* @brief Extract the ID of a COM_STMT_EXECUTE
* @brief Extract the ID from a COM_STMT command
*
* @param buffer Buffer containing a COM_STMT_EXECUTE packet
* All the COM_STMT type commands store the statement ID in the same place.
*
* @return The ID of the prepared statement being executed or 0 on failure
* @param buffer Buffer containing one of the COM_STMT commands (not COM_STMT_PREPARE)
*
* @return The statement ID
*/
uint32_t mxs_mysql_extract_execute(GWBUF* buffer);
uint32_t mxs_mysql_extract_ps_id(GWBUF* buffer);
MXS_END_DECLS

2
server/modules/protocol/MySQL/mysql_common.c
View File

@ -1637,7 +1637,7 @@ bool mxs_mysql_extract_ps_response(GWBUF* buffer, MXS_PS_RESPONSE* out)
return rval;
}
uint32_t mxs_mysql_extract_execute(GWBUF* buffer)
uint32_t mxs_mysql_extract_ps_id(GWBUF* buffer)
{
uint32_t rval = 0;
uint8_t id[MYSQL_PS_ID_SIZE];

18
server/modules/routing/readwritesplit/readwritesplit.hh
View File

@ -32,6 +32,7 @@
#include <maxscale/service.h>
#include <maxscale/backend.hh>
#include <maxscale/session_command.hh>
#include <maxscale/protocol/mysql.h>
enum backend_type_t
{
@ -213,6 +214,23 @@ public:
return 0;
}
bool write(GWBUF* buffer, response_type type = EXPECT_RESPONSE, uint64_t id = 0)
{
if (id)
{
BackendHandleMap::iterator it = m_ps_handles.find(id);
if (it != m_ps_handles.end())
{
/** Replace the client handle with the real PS handle */
uint8_t* ptr = GWBUF_DATA(buffer) + MYSQL_PS_ID_OFFSET;
gw_mysql_set_byte4(ptr, it->second);
}
}
return mxs::Backend::write(buffer);
}
private:
reply_state_t m_reply_state;
BackendHandleMap m_ps_handles; /**< Internal ID to backend PS handle mapping */

3
server/modules/routing/readwritesplit/rwsplit_internal.hh
View File

@ -75,7 +75,8 @@ SRWBackend handle_slave_is_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses
bool handle_master_is_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
SRWBackend* dest);
bool handle_got_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
GWBUF *querybuf, SRWBackend& target, bool store);
GWBUF *querybuf, SRWBackend& target,
bool store, uint64_t stmt_id);
bool route_session_write(ROUTER_CLIENT_SES *rses, GWBUF *querybuf,
uint8_t command, uint32_t type);

57
server/modules/routing/readwritesplit/rwsplit_route_stmt.cc
View File

@ -91,6 +91,28 @@ void handle_connection_keepalive(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
ss_dassert(nserv < rses->rses_nbackends);
}
static inline bool is_ps_command(uint8_t cmd)
{
return cmd == MYSQL_COM_STMT_EXECUTE ||
cmd == MYSQL_COM_STMT_SEND_LONG_DATA;
}
uint64_t get_stmt_id(ROUTER_CLIENT_SES* rses, GWBUF* buffer)
{
uint64_t rval = 0;
// All COM_STMT type statements store the ID in the same place
uint32_t id = mxs_mysql_extract_ps_id(buffer);
ClientHandleMap::iterator it = rses->ps_handles.find(id);
if (it != rses->ps_handles.end())
{
rval = it->second;
}
return rval;
}
/**
* Routing function. Find out query type, backend type, and target DCB(s).
* Then route query to found target(s).
@ -113,6 +135,7 @@ bool route_single_stmt(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
/* packet_type is a problem as it is MySQL specific */
uint8_t command = determine_packet_type(querybuf, &non_empty_packet);
uint32_t qtype = determine_query_type(querybuf, command, non_empty_packet);
uint64_t stmt_id = 0;
if (non_empty_packet)
{
@ -148,17 +171,10 @@ bool route_single_stmt(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
std::string id = extract_text_ps_id(querybuf);
qtype = rses->ps_manager.get_type(id);
}
else if (command == MYSQL_COM_STMT_EXECUTE)
else if (is_ps_command(command))
{
uint32_t id = mxs_mysql_extract_execute(querybuf);
ClientHandleMap::iterator it = rses->ps_handles.find(id);
if (it != rses->ps_handles.end())
{
char *qtypestr = qc_typemask_to_string(rses->ps_manager.get_type(it->second));
MXS_INFO("Client handle %u maps to %lu of type %s", id, it->second, qtypestr);
MXS_FREE(qtypestr);
}
stmt_id = get_stmt_id(rses, querybuf);
qtype = rses->ps_manager.get_type(stmt_id);
}
route_target = get_route_target(rses, qtype, querybuf->hint);
@ -217,7 +233,7 @@ bool route_single_stmt(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
if (target && succp) /*< Have DCB of the target backend */
{
ss_dassert(!store_stmt || TARGET_IS_SLAVE(route_target));
handle_got_target(inst, rses, querybuf, target, store_stmt);
handle_got_target(inst, rses, querybuf, target, store_stmt, stmt_id);
}
}
@ -1023,20 +1039,13 @@ static inline bool query_creates_reply(mysql_server_cmd_t cmd)
}
/**
* @brief Handle got a target
* @brief Handle writing to a target server
*
* One of the possible types of handling required when a request is routed
*
* @param inst Router instance
* @param ses Router session
* @param querybuf Buffer containing query to be routed
* @param target_dcb DCB for the target server
*
* @return bool - true if succeeded, false otherwise
* @return True on success
*/
bool
handle_got_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
GWBUF *querybuf, SRWBackend& target, bool store)
bool handle_got_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
GWBUF *querybuf, SRWBackend& target,
bool store, uint64_t stmt_id)
{
/**
* If the transaction is READ ONLY set forced_node to this backend.
@ -1065,7 +1074,7 @@ handle_got_target(ROUTER_INSTANCE *inst, ROUTER_CLIENT_SES *rses,
response = mxs::Backend::EXPECT_RESPONSE;
}
if (target->write(gwbuf_clone(querybuf), response))
if (target->write(gwbuf_clone(querybuf), response, stmt_id))
{
if (store && !session_store_stmt(rses->client_dcb->session, querybuf, target->server()))
{